1. Field of the Invention
The present invention relates to an apparatus for magneto-optical disc.
2. Description of the Prior Art
Research and development of various magneto-optical discs have achieved remarkable results these days and a wide variety of magneto-optical discs are now commercially available on the market. According to the ISO (international organization for standardization), a magnetic field applied to a magneto-optical disc by a magneto-optical disc apparatus is limited to 600 Oe (oersted). A magneto-optical recording apparatus capable of recording a writable magneto-optical disc disclosed in Japanese laid-open patent publication No. 62-175948 or a magneto-optical reproducing method capable of reproducing a magneto-optical disc of an ultra-high resolution disclosed in Japanese laid-open patent publication No. 3-88156 needs plural kinds of external magnetic fields. In this case, when a recording, e.g., overwrite is effected or a reproduction is effected, a strong external magnetic field different from a recording magnetic field or a reproducing magnetic field generated from a portion in which an optical pickup is disposed is applied to a magneto-optical disc in order to initialize a predetermined magnetic layer of, for example, a multi-layer magnetic film constructing a magnetic film.
FIG. 1 of the accompanying drawing shows a schematic plan view of a main portion of a conventional magneto-optical disc apparatus and FIG. 2 is a schematic side view thereof. As shown in FIGS. 1 and 2, when a magneto-optical recording apparatus is realized, a recording magnet 3 for generating a recording magnetic field is disposed on an optical axis of an optical pickup 2 that irradiates a magneto-optical disc 1 across the optical pickup 2 that records and reproduces the magneto-optical disc 1 in an opposing relation to the magneto-optical disc 1. An initialization magnet 4 is disposed at a different position in an opposing relation to the magneto-optical disc 1.
The initialization magnet 4 is used to generate a strong initialization magnetic field Hini of several kilooersteds as described above. Therefore, it is inappropriate that the magneto-optical disc, based on the restriction of the ISO (under which it is inhibited from being applied with a magnetic field of larger than 600 Oe) and the magneto-optical disc capable of overwrite or magneto-optical disc having special functions such as reproduction of ultra-high high solution or the like are applied to a common drive apparatus, i.e., common magneto-optical disc apparatus.
However, when the optical disc is recorded and reproduced, it is very disadvantageous for the user to properly use the magneto-optical disc based on the ISO and the special magneto-optical disc that needs the application of plural kinds of magnetic fields including a strong magnetic field on the common drive apparatus.